Electrical-contact mechanism



(No Model.)

J. P. BLAKE.

ELECTRICAL CONTAGT MECHANISM.

No. 520,351. Patented Ma 22 1894.

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BY 3 @M ATTOR N EYS.

ms unlomL umoammms COMPANY. WASHINGTON, u. c.

UNITED STATES PATENT OFFICE.

JOHN FEGGETTER BLAKE, OF NEW HAVEN, CONNECTICUT.

ELECTRICAL-CONTACT MECHANISM.

SPECIFICATION forming part of LettersPatent No. 520,351, dated May 22,1894.

Application filed March 3, 1894:- Serial No. 502,194. (No model.)

To all whom it may concern:

Be it known that I, J OHN FEGGETTER BLAKE, a citizen of the UnitedStates, residing at New Haven, in the county of New Haven and State ofConnecticut, have invented new and useful Improvements inElectrical-Contact Mechanism, of which the following is a specification.

The object of this invention is to provide an electrical contactmechanism which is readily applicable to a pressure gage as set forth inthe following specification and claim and illustrated in the annexeddrawings, in which Figure 1 is aface view of the contact mechanism. Fig.2 is a section along as a: Fig. 1.

In the drawings the letter A indicates the well known glass plate orcrystal covering of a pressure gage. The glass or transparent plate isset rotatably or adjustably in place and is provided with acontactorpost B. The glass plate A forms an insulating support or carrier for thecontact B. This contact B is adapted to engage or strike the index orhand C and when the plate A is properly rotated the post B will carrythe index C from say the zero point to indicate any suitable figure asfor example fifteen. When the pressure acting on the gage rises abovethis point, the index C Will be carried beyond the said figure, and thecontact between index C and post Bis then broken. Supposing the contactestablishes a circuit operating a motor or pump (not shown) generatingpressure indicated by the gage, then if such pressure rises above thedesired point the contact is broken, and the circuit being interruptedthe motor will stop until the pressure falls below I the desired point,when the contact is restored and the actionof the motor recommences.

The glass or crystal A is supported in any convenient manner as by aring or bezel D adj ustably engaging a groove or shoulder E by means ofset screws F. The groove or shoulder E is formed in the gage case G andthe ring D with glass A can be rotated to the required position on thecase G, and subsequently rigidly fixed to the case in the position towhich adjusted by tightening the set screws F. The ring D and glass Aform a cover or lid.

By having the conductors H I respectively engaged by or connected to thecontact B and to a binding post K on ring D the contact B and post Kwill be set or rotated together and the conductors H I will be kept inthe same relative position. It is manifest however that the binding postK can be otherwise located if seen fit, as for example on the case G.

In my experiments I have found that a pumping action generating pressurein the gage is liable at times to cause the index C to make short breaksor jumps away from contact B, thus causing arcs. To avoid this objectionI form the inlet to the gage with a diminished diameter as L and alsoprovide a porous filling such as cotton M, whereby the pressure in thegage is caused to rise or fall steadily, the steadily rising pressurewhen sufficiently intense causing the index 0 to make a permanent orclean break from contact B, which break is not restored until thepressure steadily falling has passed below the required intensity.

It is manifest that the device would be efiicient if the ring D werefixed and the glass A made movable or adjustable in ring D but I preferto make an adjustable cover A D as shown.

What I claim as new, and desire to secure by Letters Patent, is-- Apressure gage consisting of a gage body provided with an annular grooveor shoulder E, a cover composed of a ring or bezel rotatable on the gagebody and having a glass plate or crystal, a set screw carried by thecover and engaging the groove or shoulder to rigidly clamp the cover inany required position on the gage body, and a contact carried by thecover and adapted to engage and set the index of the gage, substantiallyas described.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

JOHN FEGGETTER BLAKE.

Witnesses:

J AKOB HAHN, CHARLES F. BOLLMANN.

